/**
* Takes the results of running linkWalkFirstPhase and creates an m/r job from them
*
* @param firstPhaseResult the results of running linkWalkfirstPhase.
* @return the results from the intermediate bkeys of phase one.
* @throws IOException
*/
private MapReduceResult linkWalkSecondPhase(final MapReduceResult firstPhaseResult)
throws IOException {
try {
@SuppressWarnings("rawtypes")
Collection<LinkedList> bkeys = firstPhaseResult.getResult(LinkedList.class);
BucketKeyMapReduce mr = new BucketKeyMapReduce(this);
int stepCnt = 0;
for (LinkedList<List<String>> step : bkeys) {
// TODO find a way to *enforce* order here (custom
// deserializer?)
stepCnt++;
for (List<String> input : step) {
// use the step count as key data so we can aggregate the
// results into the correct steps when they come back
mr.addInput(input.get(0), input.get(1), Integer.toString(stepCnt));
}
}
mr.addReducePhase(new NamedErlangFunction("riak_kv_mapreduce", "reduce_set_union"), false);
mr.addMapPhase(
new JSSourceFunction("function(v, keyData) { return [{\"step\": keyData, \"v\": v}]; }"),
true);
return mr.execute();
} catch (ConversionException e) {
throw new IOException(e.getMessage());
} catch (RiakException e) {
throw (IOException) e.getCause();
}
}
/*
* (non-Javadoc)
*
* @see
* com.basho.riak.client.raw.RawClient#fetchIndex(com.basho.riak.client.
* raw.query.IndexQuery)
*/
public List<String> fetchIndex(IndexQuery indexQuery) throws IOException {
final MapReduce mr = new IndexMapReduce(this, indexQuery);
mr.addReducePhase(NamedErlangFunction.REDUCE_IDENTITY, Args.REDUCE_PHASE_ONLY_1);
// only return the key, to match the http rest api
mr.addReducePhase(
new JSSourceFunction("function(v) { return v.map(function(e) { return e[1]; }); }"),
Args.REDUCE_PHASE_ONLY_1);
try {
MapReduceResult result = mr.execute();
return new ArrayList<String>(result.getResult(String.class));
} catch (RiakException e) {
throw new IOException(e);
}
}